NAME____________________________
Final Examination
Vision Science 117: Oculomotor Functions and Neurology
Spring 1996
Circle all correct answers on the answer sheet. More than one or none may be correct. When you have completed it, retain this copy of the test and turn in your answer sheet.
GOOD LUCK!
1. Which of the following are synonyms for fixation disparity?
a. retinal image disparity
b. micro strabismus
c. anomalous correspondence
d. retinal slip
2. Which type of forced duction curve is associated with rapid adaptation to base in prism?
a. I
b. II
c. III
d. IV
3. Which of the following can produce an exo fixation disparity?
a. BO prism
b. minus lenses
c. esophoria
d. exotropia
4. Which of the following influences the slope of the ZCSB?
a. far phoria
b. amplitude of accommodation
c. calculated AC/A ratio
d. positive relative convergence
5. Which of the following are expeded to the low values in near esophoria?
a. amplitude of accommodation
b.AC/A ratio
c. PRA
d. PRC
6. Which of the following will increase esophoria?
a. B.I. prism
b. plus lenses
c. adaptation to BO prism
d. paresis of the medial rectus
7. Which of the following are stabilizing eye movements?
a. saccades
b. pursuits
c. VOR
d. OKN
8. Which of the following are tracking EM?
a. saccades
b. pursuits
c. VOR
d. OKN
9. Which of the following stimulate upward EM?
a. horizontal OK
b. anterior OK
c. posterior OK
d. ultricles
10. Which muscles of the left eye lie in the plane of the left posterior canals?
a. IO
b. SO
c. IR
d. SR
11. Which muscles constrict with stimulation of the left anterior canals?
a. LSO
b. LIO
c. RSR
d. RIR
12. Which of the following are actions of true LSO?
a. depression when left eye is abducted
b. excyclo torsion when LE is abducted
c. abduction when LE is abducted
d. elevation when LE is depressed
13. Clinical uses of OKN include
a. objective measures of visual acuity
b. evaluation of maturity of infants
c. test for small scotomas (visual fields)
d. test for early onset esotropia
14. Which of the following are components of the infantile squint syndrome?
a. dissociated vertical deviation
b. asymmetric monocular horizontal OKN
c. Latent nystagmus
d. accommodative esotropia
15. Which of the following are functions of saccades?
a reset the eyes during visual stabilization in OKN
b. maintain fixation of a stationary target
c . visual search
d. correct positional errors of pursuits
16. Which of the following is described by the Main Sequence for saccades?
a. velocity
b. amplitude
c. duration
d. latency
17. Which of the following control the velocity of saccades?
a. burster firing frequency
b. integrated burster activity in tonic cells
c. duration of the burst
d. pause cells
18. Which of the following initiate saccades?
a. fixation cells in the superior colliculus
b. inhibition of pause cells
c. burster cells
d. tonic cells
19. Which of the following describe the control characteristics of saccades?
a. they are quasi-ballistic
b. they utilize visual feedback during their execution
c. they have a longer latency than any of the other classes of eye movements
d. they can not predict motion of repetitive stimuli
20. Which of the following contribute to saccadic suppression?
a. backward masking (meta-contrast)
b. depressed visual sensitivity
c. retinal image smear
d. computing abrupt changes in visual direction
21. Which of the following are typical of combined head and eye movements?
a. saccades without head movements rarely exceed 15 degrees in amplitude
b. stimuli exceeding 5 degrees typically evoke a combined head and eye movement
c. the eye reaches the target before the head in combined head-eye movements
d. the VOR and OKN are suppressed or nulled during head tracking of visual targets
22. Which of the following properties of saccades can be modified by stimuli during the first 90 msec of the latency period?
a. amplitude can be altered
b. direction can be altered midflight
c. latency can be reduced in subsequent corrective saccades
d. disparity can cause saccades in opposite directions (disjunctive)
23. Which of the following describe saccades in asymmetric vergence?
a. they are unequal in direction in the two eyes
b. they are unequal in amplitude in the two eyes
c. they are triggered by the same pause neurons that triggers vergence
d. they occur in asymmetric vergence stimulated by monocular accommodation
24. Which of the following are true concerning the supranuclear control of saccades.
a. saccades require an intact frontal eye field
b. saccades require an intact superior colliculus
c. the occipital pathways are relayed primarily via the superior colliculus
d. stimulation of one cortical hemisphere evokes saccades to the same side
25. Which of the following movements that occur during "steady" fixation can be error correcting?
a. slow drifting eye movements
b. micro saccades
c. vergence drift
d. high frequency tremor exceeding 50 Hz
26. Which of the following are functions of pursuits?
a. suppress the VOR during head tracking
b. slow control of steady fixation
c. suppress OKN while tracking a moving target
d. foveate a moving target
27. Which of the following are true concerning fixation in darkness?
a. the eye remains within 1/4 degrees of its intended direction in dark
b. drifts are faster in the dark than light
c. saccades are all error producing in the dark
d. auditory stimuli evoke fixation saccades in the dark
28. Which of the following can stimulate pursuits
a. visual motion relative to the head
b. retinal position errors
c. moving auditory stimuli in darkness
d. arm proprioception in darkness
29. Which of the following describe the control characteristics of pursuits?
a. they are ballistic
b. they utilize visual feedback during their execution
c. they have the shortest latency than any voluntary eye movement
d. they can not predict motion of repetitive stimuli
30. Which of the following describe the pursuit response to a ramp stimulus?
a. the initial 10-20 msec is independent of target velocity
b. the initial 100 msec is not influenced by visual feedback
c. pursuit velocity is related to initial target velocity near the end of the
open-loop phase
d. pursuits can correct position errors by anticipating
when the eye will foveate a target
31. Which of the following regions contribute to the control of pursuits?
a. primary visual cortex
b. frontal eye fields
c. PPRF
d. DLPN
32. Which of the following are always active during rightward horizontal pursuits?
a. left MST
b. right occipital cortex
c. pursuit centers right half of the brainstem
d. left vestibular nuclei
33. Which of the following are symptomatic of lesions of the right cerebral hemisphere?
a. left hemianopsia
b. inability to make leftward saccades
c. inability to perceive rightward motion
d. rightward jerk nystagmus
34. Which of the following would be a way to focus (accommodate) a near target?
a. shorten the axial length
b. move the ocular lens forward toward the cornea
c. increase the radius of corneal curvature
d. increase the isoindical gradient of the lens
35. How is the Scheiner pupil used to assess accommodation?
a. it forms a double image of the pupil on the retina
b. it provides separate views of objects through non-axial portions of the lens
c. it is not influenced by spherical aberration of the eye
d. it provides a large depth of focus that clears images at all viewing distances
36. Which of the following changes in the lens occur when accommodation increases?
a. the lens diameter decreases
b. the lens is affected by gravity
c. the radius of curvature of the posterior surface of the lens decreases
d. the lens thickness decreases
37. The relaxation theory of accommodation proposes ?
a. the lens increases in power with pressure applied by the suspensory ligament
b. the anterior zonular fibers move forward during accommodation
c. the lens capsule thickness variations mold the relaxed lens
d. the posterior zonular fibers move forward during accommodation
38. Which of the following changes could contribute to presbyopia?
a. reduction of the index gradient of the lens
b. reduced elasticity of the lens
c. reduced elasticity of the suspensory ligament
d. increased diameter of the lens
39. Which of the following contribute to night myopia?
a. spherical aberration
b. Purkinje shift
c. reduced visual acuity in scotopia
d. resting focus of accommodation
40. Which of the following could be used as "odd-error" information for accommodation?
a. blur
b. perceived distance
c. chromatic aberration
d. lens power oscillations
41. Which of the following Maddox components will coarsely adjust accommodation?
a. Blur
b. Convergence
c. perceived proximity
d. tonic resting focus
42. Which of the following influence the depth of focus of the eye
a. Visual acuity
b. pupil size
c. spherical aberration
d. target size
43. Which of the following would occur if the index of refraction of the lens cortex increased to match the index of the nucleus.
a. The eye would become less myopic
b. The myodiopter would increase
c. light would be refracted more within the lens than at its surfaces
d. the lens would be more elastic
44. Which of the following exploits chromatic aberration of the eye?
a. blur driven accommodation
b. the duochrome test
c. Scheiner pupil
d. proximal accommodation
45. Which of the following are altered by adaptable tonic vergence
a. anatomical position of rest
b. physiological position of rest
c. prism -induced uniform phoria
d. aniso-spectacle induced non-comitant phoria
46. Which of the following events require orthophorization
a. growth of the interpupillary distance
b. anisometropic contact lens correction
c. abnormally large or small AC/A ratios
d. paresis of an ocular muscle
47. Which of the following describe the control characteristics of vergence?
a. they are ballistic
b. they utilize visual feedback during their execution
c. they have a shorter latency than accommodation
d. they can not predict motion of repetitive stimuli
48. Which of the following is true about the AC/A
a. it is non-linear when the gradient is tested at various viewing distances
b. it is independent of the speed or velocity of accommodation
c. it is stable from month to month until the onset of functional presbyopia
d. it is stimulated by both tonic and phasic accommodation
49. Which of the following will produce an increase in eso-fixation disparity?
a. plus lenses c. base out prism
b. minus lenses d. base in prism
50. What factors influence the accommodative response at the four accommodative stimuli indicated by points a,b,c,d in the figure below.
51. ( 4 points) Calculate the expected amplitude of accommodation of a 27 year old?
52. ( 4 points) Calculate the age of a functional presbyope with a 33cm near working
distance.
53. ( 8 points) A child has a 5 cm PD and views a near target at 20cm
a) Calculate the convergence stimulus in meter angles.
b) Calculate the convergence stimulus in prism diopters.
54. ( 8 points) A patient with a 6 cm PD has a distance phoria of 3 exo and a near phoria measured at 33 cm of 6 exo. If a minus 2 diopter lens is worn at the same near viewing distance the near phoria becomes orthophoric.
a) What is the calculated AC/A?
b) What is the gradient AC/A?
55. (16 points) Calculate the following values based on the graph on your answer sheet. All near measures are made at a 40 cm viewing distance. The patient has a 6 cm PD.
a. the width of the zone of clear single binocular vision
b. positive relative convergence at near
c. positive fusional convergence at near
d. negative relative convergence at near
e. negative fusional convergence at near
f. positive relative accommodation at near
g. negative relative accommodation at near
h. AC/A ratio
56. (10 points) On the graphical analysis plot (located on your answer sheet), label the following components:
demand line phoria line
break points blur points
base out limit base in limit
peak of the zone